In the drilling of oil and gas wells, whether offshore or onshore, rotary drilling techniques require the use of drilling mud circulated through the borehole during the drilling process. Typically, the drilling rig is provided with a drilling mud circulation and cuttings collection system. In such a system, the drilling mud is pumped from a mud holding tank, through mud supply lines, down through the borehole and returned to the surface of the borehole. This circulating drilling mud carries the drill cuttings that are produced as the drill bit advances in the borehole to the surface of the well.
The drilling mud and that is returned to the surface, along with the carried drill cuttings, is typically transferred to a shaker or sieving device. The shaker or sieving device is used to remove the carried drill cuttings from the drilling mud. The drilling mud, absent the removed drill cuttings, is then re-circulated to the borehole and the drill cuttings that are removed by the shaker are typically collected in drill cuttings collection trough that is in communication with the shaker.
The drill cuttings in the cuttings collection trough are typically comprised of bits of shale, sand, hard clays, or shell that may have been present in the borehole. The drill cuttings are often coated with or contain residual liquids such as drilling mud or other liquids that may have been present in the borehole. The drill cuttings and the residual liquids may contain hazardous environmental contaminants that will require treatment before their ultimate disposal.
These cuttings with these residual liquid contaminants are typically conveyed to a dryer for removal of the residual liquids. The cuttings and any remaining liquids then transferred to storage boxes or containers where they are retained on the rig or at the well site until they are removed for further treatment and disposal at a later time.
Various techniques are currently utilized to convey the drill cuttings and associated residual liquids from the drill cuttings collection trough to a dryer and then to storage boxes or container. These techniques include the use of conveyors, chutes, and vacuum lines.
The present invention is designed to provide a novel drill cuttings dryer and cuttings handling apparatus that utilizes a vacuum suction both to assist and enhance the removal of the associated residual liquids from the drill cuttings and to serve as the conveyance system for the drill cuttings and the associated residual liquids treat during their collection and treatment.